An airbag device is designed to absorb kinetic energy of a driver when a vehicle body receives an impact of a predetermined value or more. Heretofore, studies have been made on how and where to appropriately arrange such an airbag device in a motorcycle, the airbag device integrally housing components such as a folded airbag and an inflator for inflating and deploying the airbag.
Patent Document 1 (Japanese Patent Application Publication No. 2007-314117) generally discusses a structure for a scooter-type motorcycle in which a low-slung foot rest for the rider is formed between a steering handlebar and a rider seat. In the structure discussed in Patent Document 1, an airbag device is installed so as to be housed inside a cover member arranged upright on the front side of the low-slung foot rest in a front-rear direction of the vehicle body so as to cover the spindle of the steering handlebar.
However, because the airbag device needs to inflate and deploy the airbag in front of the rider at a proper position, a motorcycle, in particular, does not have many location possibilities for installing the airbag device. Additionally, wasted space may be created around the housing, when a housing case of the airbag is made to have, for example, a substantially rectangular-solid shape and is installed in a vehicle body of the motorcycle. Accordingly, the shape of the housing case and its installing position still need to be devised in order to further efficiently install the airbag device. Furthermore, there exists a problem in folding the airbag so that the airbag can be efficiently housed in the housing case. Patent Document 1 does not really take such issues into account.